The kinetics of mineralization and demineralization of enamel, dentine, and calculus will be studied at constant under-and super-saturations. Experimental conditions will range from the production of softened surfaces to the formation of subsurface lesions both in enamel and dentine. Remineralization measurements will be made over a range of ionic strength, concentration, and pH typical of those in the mouth. The extent of demineralization and lesion depth will be related to the rate and extent of removal of ions such as calcium, phosphate, carbonate, and fluoride by using multiple specific ion electrodes for controlling the activities of calcium and hydrogen ions by the automated addition of titrant solutions. The nature of the calcium phosphate phases which are involved in the demineralization and remineralization reactions will be investigated and solids will be characterized by scanning and transmission electron microscopy, electron microprobe, infrared, x-ray diffraction, specific surface area, particle size distribution, and surface charge analysis. The influence, upon both de- and re-mineralization, of cariogenic and cariostatic agents, ions such as magnesium, strontium, fluoride, and carbonate will be investigated over a range of concentrations. In addition, the influence of human saliva, synthetic compositions, and separated purified salivary mucins and cysteine containing phosoproteins on the rates of reactions will be investigated using enamel, dentine, calculus, and synthetic calcium phosphates. The development of effective methods for remineralizing the lesions will be emphasized.